Fluoropyrimidine therapy: hyperbilirubinemia as a consequence of hemolysis

Hemolytic anemia has been noted during treatment with a variety of chemotherapeutic agents. We observed mild compensated hemolytic anemia in a patient receiving capecitabine during a randomized, controlled trial of adjuvant therapy. In order to investigate the hypothesis that hemolysis is the underlying cause of the hyperbilirubinemia sometimes observed during capecitabine treatment, we evaluated factors associated with hemolysis in ten patients. Factors were also analyzed in ten patients receiving 5-fluorourocil/leucovorin (5-FU/LV).

Twenty chemotherapy-naïve patients undergoing surgery for Dukes' C colon cancer were included in the phase III, 'X-ACT' trial, and randomized to receive 24-week adjuvant treatment with either oral capecitabine (eight cycles of 1,250 mg/m2 twice daily for 14 days, followed by a 7-day rest period) (n=10) or 5-FU/LV administered according to the Mayo Clinic regimen (six cycles of LV 20 mg/m2 followed by 5-FU 425 mg/m2, administered as an i.v. bolus on days 1-5 every 28 days) (n=10). Ten patients randomized in each treatment arm were evaluated. Hemolytic parameters evaluated included bilirubin, lactate dehydrogenase, haptoglobin, and reticulocytes.

Seven patients receiving capecitabine and three patients receiving 5-FU/LV experienced grade 1/2 elevations of bilirubin during the 24-week treatment period. In most cases, hyperbilirubinemia was associated with concomitant alterations in other hemolytic parameters. Five episodes of grade 1 compensated hemolytic anemia were reported in four capecitabine-treated patients, all of which were associated with hyperbilirubinemia.

Adjuvant treatment with capecitabine or 5-FU/LV in a small sample of patients with Dukes' C colon cancer was associated with alterations in hemolytic parameters. These alterations, in particular hyperbilirubinemia, were associated in some patients with low-grade compensated hemolytic anemia. All changes were clinically insignificant, fully reversible, and may represent a fluoropyrimidine class effect. Further studies are indicated to evaluate the incidence and implications of this effect.